I've had this tank for about three years. About a year ago the co2 regulator developed a leak after the first refill, so I just took it out. I originally bought the dual stage regulator by itself off ebay for $70 new. Too good to be true so I wasn't surprised it stopped working. I added the needle valve, check valve, and solenoid.The tank went to crap without co2. Moneywort, crypt and moss was all that survived and not that well. I bought another regulator and it leaked too, figured out I wasn't tightening the regulator to the co2 tank well enough. So I returned the new regulator and went back to my original regulator and it works fine. Pretty dumb mistake.
I was using a current USA light but sold it when I got rid of the co2. I went back to the new improved stock light which is much better than the old one fluval used to provide with their tanks. Light is on 10 hours a day and co2 is on 1 hour before and off 1 hour before the lights.
I make RO water and remineralize with seachem equilibrium, adding 2 grams of equilibrium to 3 gallons of RO water and changing 2.5 gallons a week. The water is 4gh and 0kh and around 120ppm. Dosing EI and using osmocote root tabs. Currently not dosing as I added too much osmocote and ended up over dosing ferts. Everything survived but the plants are little too dark green and I had to move the nerite snail to my other tank until I could do a couple extra water changes. Things seem to be good now.
Stocking list: I bought some Rotala Wallichii, Staurogyne Repens, Lobelia Cardinalis Dwarf, and Echinodorus Parviflorus to start the tank over. I already had the bronze crypt wendtii, bacopa monnieri, anubias nana petite, Hygrophila sp all of which are doing much better with co2. I now know why fissidens fontanus is called the phoenix moss. I had it in the tank before I took out the co2 but it completely died away then suddenly came back when I added co2. Just sprouted right from the gravel, like a phoenix from the ashes.
Livestock: 6 amano shrimp, a few cherry shrimp from my other tank, 1 CPD, 5 neon tetras, 1 clown pleco, 1 nerite snail, 1 scarlet badis.
Attached pictures: first one is the most recent then the next is on July 21 and each photo is about a week apart. Last photo is what my tank looked like a year ago when I last had co2.
Here are some more pics from before: http://imgur.com/a/TDGUo